Wafer or disk carriers are used with semiconductor manufacturing equipment such as wafer handlers to store and transport semiconductor wafers in processes for making semiconductor devices such as integrated circuits. A common design for such wafer carriers stacks a plurality of the wafers in close proximity to each other, with each wafer having its own slot within the carrier. It is important that the wafers be precisely spaced and aligned within the carrier so that when the carrier is in use, the wafer handlers are properly aligned with the individual wafers. Misaligned wafers can result in damage to the tooling, breakage of the wafers or improperly etched wafers.
It can be difficult to determine from a visual inspection whether a carrier is properly dimensioned. Through repeated use, or trauma, a carrier can lose its proper shape. Additionally, new carriers often do not match specifications. As a result, users commonly rely on “known good” carriers that have been used successfully in the past, which can result in moving wafers from loaded carriers that are of unknown quality to known good carriers. Such changing of carriers can increase the contamination of the wafers, and may even result in additional broken wafers.
What is needed is a device to easily and quickly verify whether a disk carrier complies with the desired size and shape specifications. Preferably the device is simple and economical to use and construct.